Cut the strips so they are 4" shorter than the final width of your runner. The strips should be approximately 1/2" from and parallel to the corner between the riser and the tread. For consistent placement make a spacer of two strips taped together to determine how high to place the tackless strips on the riser(image 1). Attach a tackless strip centered on the riser and on the back of each tread (image 2). The points of the strip should face the corner.
Roll out the length of carpet needed to run the length of the stairs and cut it approximately 3" wider than the finished runner will be. Turn the carpet upside down, and snap a chalk line on each side so that the distance between the chalk lines is equal to the width of the runner.
Fold the edges of the carpet under, and center the carpet on the bottom edge of the steps (image 1). Use the awl to push the carpet onto the tackless strip (image 2).
Use a knee kicker to push the carpet tight into the corner of the tread and riser while using a stair tool to wedge the carpet into the corner between the tread and the riser. Repeat steps six and seven as you work your way up the stairs.
If necessary, use the awl to pull the bottom of the fold out so that the edges of carpet are straight (image 1). When the edges of the carpet are straight, staple them in place again wiggling the stapler in between the fibers of the carpet (image 2).